91 XJ40. At night with the headlights on, the gauges... speedo, tach backlight is no more.

The VCM has an on/off switch and lights up fine (including the VCM's visual monitor at the bottom of the cluster... operable), that show the car's mileage etc.

Of course, I checked the variable button on left side of the steering wheel.. it was on and at it's brightest setting.

Are there bulb(s) to replace, EASILY? If I have to remove the cluster module etc to get to it, it ain't gonna happen... But any advise out there?


JagBro

 

If all of the cluster bulbs are out at once, then its unlikely that they all bad at once. There is a fuse in the center fuse pack that runs the instrument panel- Second fuse from the right. Have a look there, although there may be another fuse that only powers the dash lights. Don B has done write ups on instrument panel repairs, try searching instrument panel lights in this forum. Good luck

 

Hi JagBro,

Jerry is right that if all your instrument lights are out, it is unlikely a bulb problem. In addition to a blown fuse as Jerry mentioned, loose or corroded electrical connectors on the back of the instrument cluster are a known issue. The other key suspect is the dimmer module, which is what the dimmer knob on the left side of the steering column is attached to. The modules are known to fail, causing a loss of all lamps that are controlled by the dimmer. You can bypass the dimmer module with jumper wires to see if the lamps illuminate. If so, the module is dead.

I don't have photos showing how to change the module, but photos in the album below show how it is removed. Unfortunately the large images are still down at Jag-Lovers but the thumbnails and descriptions are visible:

XJ40 Ignition Switch Replacement

Here are a few more albums that may be helpful:

XJ40 Knee Bolster Removal Driver's Side

XJ40 Steering Column Cowl

If you determine the problem is inside the instrument cluster, it's simple to remove, and the bulbs are easy to access, though replacements are expensive from Jaguar ($12+ each last time I checked) and unavailable from aftermarket sources. You can reuse the plastic bases and replace the bulbs with the proper size grain-of-wheat type bulbs or LEDs, or do as I did and pay $40 on eBay for a used instrument cluster that was complete with a full set of working bulbs.

XJ40 Instrument Cluster Part 1 of 2

XJ40 Instrument Cluster Part 2 of 2

Cheers,

Don

 

Thanks guys... I just checked fuses, all ok. I will tackle this cluster module at some point after a few Yosemite Sam, under my breath curse words (ohhhh-wizzle-scrazzle-ricken-frazzell-cazen-kazle-fraken-riker), and so forth...

Jagbro

 

Is this dimmer module for sale somewhere?, Can't find one....

 

I located a dimmer switch, just arrived. However, if you notice the black connector on the new switch does not have any additional wiring directed anywhere else.

The photo my existing switch (still in the steering column), has ADDITIONAL wiring from the black connector to a green connector mounted in a bracket under the column. Sorry for the picture, it's awkward under there.

What's going on here? I definitely don't want to do any cutting/ splicing of wires. Is this just the wrong switch? What can I tell the sender, is this green connector powering an optional accessory I can tell the seller about, or am I looking at all of this wrong?

If I install the new switch without (by-passing) the green connector, what am I losing?

 

Hi Jagbro,

It's possible the dimmer you received is for an earlier or later car. Check the schematics at jagrepair.com (I think they're under the XJ6 & XJ12 section rather than the XJ40 section). Compare the dimmer wiring on the instrument lighting diagrams for your '91 to the one for the early cars ('88-'89) and later cars ('93-'94).

Cheers,

Don